Arne Martinsson

Co-release of neuropeptide Y and catecholamines during physical exercise in man

Venous plasma levels of neuropeptide Y-like immunoreactivity (with chromatographic properties of synthetic neuropeptide Y) increased in parallel with catecholamines, heart rate and blood pressure during graded physical exercise in man. The plasma levels of neuropeptide Y correlated better with the levels of noradrenaline than adrenaline, suggesting release of a neural origin. Taken together with previous results, this suggests that neuropeptide Y is released together with noradrenaline upon sympathetic activation during physiological conditions in man. Determinations of plasma neuropeptide Y may therefore be valuable in the assessment of sympathetic nerve activity.

IL-6 and IL-1 receptor antagonist in stable angina pectoris and relation of IL-6 to clinical findings in acute myocardial infarction

Abstract. Gabriel AS, Ahnve S, Wretlind B, Martinsson A (Karolinska Institute and Huddinge University Hospital, Stockholm, Sweden). J Intern Med 2000; 248: 61–66.

Effect of epinephrine infusion on chest pain in syndrome X in the absence of signs of myocardial ischemia

Eight female patients (aged 51 to 65 years) with New York Heart Association class II angina pectoris, normal coronary angiograms, normal hyperventilation, and abnormal exercise stress tests (chest pain and ST depression), and 5 sex- and age-matched controls participated in this study. Epinephrine was given intravenously to both patients and controls at 5-minute intervals in doses of 0.1, 0.2, 0.3, 0.4, and 0.6 nmol/kg/min. After rest (15 minutes), the alpha-adrenoceptor antagonist phentolamine or placebo was administered intravenously to patients in a double-blind, crossover study on 2 separate occasions in doses of 250 micrograms/min for 5 minutes and 500 micrograms/min for the next 10 minutes; the epinephrine infusion was repeated. Blood pressure, heart rate, and electrocardiogram were monitored continuously and pain was estimated on the Borg CR-10 scale. On a third occasion, chest pain was induced in patients using the same epinephrine protocol during echocardiographic monitoring. In the control group, all patients received the maximal epinephrine dose. No chest discomfort or pain developed. In the patient group, the maximal tolerable epinephrine dose (0.39 +/- 0.19 nmol/kg/min) decreased diastolic pressure (-14 +/- 9 mm Hg, p < 0.01) and increased heart rate (+24 +/- 10 beats/min, p < 0.01), not statistically different from the control group. Pulse pressure increased in the patient group (27 +/- 17 mm Hg, p < 0.01) but not in the controls. Left ventricular ejection fraction at baseline was within reference limits (58% to 75%) and did not change during epinephrine infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

|[beta]|-Adrenoceptor Function in White Blood Cells from Newborn Infants: No Relation to Plasma Catecholamine Levels

ABSTRACT: The maturity of β-adrenoceptors in newborn infants was studied in relation to the catecholamine surge during labor. Umbilical blood was collected at birth from 12 infants delivered vaginally and 13 infants delivered by elective cesarean section. Granulocytes and lymphocytes were isolated. Receptor numbers and binding affinity were determined in the granulocytes by incubation with 125Iiodohydroxybenzylpindolol. Receptor responsiveness was tested by assessing isoproterenol-induced cyclic AMP accumulation in lymphocytes. Significantly higher plasma noradrenaline, adrenaline, and dopamine concentrations were found in infants born vaginally (108; 8.9; 0.9 nmol/ liter, respectively, median values) as compared with those delivered by cesarean section (11.0; 2.4; 0.2 nmol/liter). No significant differences in β-adrenoceptor binding sites (receptor number: 39.2 ± 2.6 versus 44.7 ± 5.9 fmol/mg protein and binding affinity: 66.6 ± 7.8 versus 65.0 ± 6.2 pM) or responsiveness (maximal isoprenaline induced cAMP formation 52.4 ± 10.3 versus 40.6 ± 8.9 pmol/106 cells) were found between the two groups of infants. Lymphocyte β-adrenoceptor sensitivity was similar to that found in adults.The β-adrenoceptors on whole blood cells seem to be mature at birth and have the same responsiveness as in adults. The higher catecholamine surge during vaginal delivery as compared to elective cesarean section does not seem to affect β-adrenoceptor function. Our results do not support the idea that reduced β-adrenoceptor function is the cause of the previously observed inappropriately small cardiovascular and metabolic responses to the exceptionally high plasma catecholamine concentrations at birth.

Reduced β2-Adrenoceptor Sensitivity in Normal Pregnancy but Not in Pregnancy-Induced Hypertension

β2-Adrenoceptors on lymphocytes from healthy nonpregnant and pregnant women and patients with pregnancy-induced hypertension (PIH) were studied in vitro by a radioligand binding technique (

Improvement of the isoprenaline infusion test by plasma concentration measurements

A simple and sensitive method for the determination of isoprenaline (ISO) in plasma by high performance liquid chromatography (HPLC) with electrochemical detection is presented. Blood pressure and heart rate responses to i.v. infusion of ISO (15, 38 and 76 ng/kg/min) were studied in 15 subjects. Blood samples for ISO analyses were drawn after 7.5 min infusions on each dose level. A four- to six-fold interindividual variation in the venous plasma concentrations of ISO was found. Comparisons were made between estimates of the sensitivity to ISO from concentration-effect and dose-effect curves for both heart rate and diastolic blood pressure responses. Despite an overall correlation between the two methods of estimating ISO sensitivity, individual estimates of sensitivity differed markedly due to the differences in the plasma concentrations attained during infusions of standardized doses of ISO. The venous plasma concentration of ISO required to elevate heart rate by 25 beats/min (CC25) varied between 0.3 and 1.7 nM, whereas the corresponding dose of ISO (CD25) varied between 10 and 27 ng/kg/min.

The Glycoprotein IIb/IIIa Platelet Receptor Blocker Tirofiban, but Not Heparin, Counteracts Platelet Aggregation in Unstable Angina Pectoris

In this study, despite concomitant aspirin treatment, tirofiban, but not heparin, reduced platelet aggregation in patients with acute myocardial ischemia. Platelet aggregation was determined with 2 independent methods, filtragometry and whole blood aggregometry.